Kognity IB Physics A.0 Measurements & Uncertainty (id: d206553aa)

[单选题]
The time for two events, a and b, o7vxaau*1gg+ez / 8 oq0h+aigare measurewmn pz,snth3xiery4.2(6j m ; d to be $(5.1 \pm 0.1)s$ and $(4.9 \pm 0.1)s$ respectively. In which of the following quantities is the fractional(percent) uncertainty the smallest?

A. $a+b$
B. $a-b$
C. $a \times b$
D. $a/b$


参考答案:  A


本题详细解析:
C and D will both have iden8mgbee6b mtn8 mlf1s-)wdm/ -tical fractional uncertainties. They cannot both be the se6mnb bw8t1d - l /f8s)-mmmgemallest, so they must both be incorrect. A and B will have the same absolute uncertainty (0.2 s), but A is a large number (10) compared to B (0.2). Hence fractional uncertainty of A is the smallest.